JPH02150111A - Mechanical filter for compound longitudinal oscillation - Google Patents

Abstract

PURPOSE:To accurately arrange input and output side electrodes at the prescribed position of a piezoelectric member by polymerizing and fixing input and output electrodes in which input and output signals formed with conductive thin films are supplied to oscillators on the input and output sides. CONSTITUTION:On an input side longitudinal oscillation tone piece 32, the input side electrodes 44a and 44b of thin film formed with a conductive solvent by using the technique of screen process printing, etc., or of metallizing material formed by using a vacuum vapor-deposition or sputtering method are polymerized and fixed. Similarly, on an output side longitudinal oscillation tone piece 34, the output side electrodes 46a and 46b of conductive thin film are polymerized and fixed. Thereby, it is possible to comparatively accurately arrange the input and output side electrodes 44a, 44b, 46a and 46b at the prescribed positions of the piezoelectric members 32 and 34.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a composite longitudinal vibration mechanical filter. By polymerizing and fixing the input electrode to which signals are supplied and the output electrode to derive output signals, it becomes possible to calculate and analyze characteristics using only constants of piezoelectric materials, This invention relates to a composite longitudinal vibration mechanical filter that can achieve uniformity of characteristics in mass production by adopting the above.

[Background of the Invention] Recently, mechanical filters have been widely used in communication equipment and the like as an intermediate between LC filters and crystal filters. This is because mechanical filters have excellent selection characteristics due to their good Q value characteristics, and are also excellent in stability against temperature changes and can be miniaturized.

The first example of this type of composite longitudinal vibration mechanical filter is
As shown in the figure. As can be understood from the figure, the composite longitudinal vibration mechanical filter has an input side longitudinal vibration sound piece 2 and an output side longitudinal vibration sound piece 4, which are arranged on the same plane and made of a metal material or the like. are doing. The input side longitudinally vibrating sound bar 2 and the output side vertically vibrating sound bar 4 are integrally connected by constant elastic coupling members 6 and 8. In this case, a support member 1 is provided at the outer central part of the input side longitudinal vibration sound piece 2 and the output side vertical vibration sound piece 4.
0 and 12 are provided protrudingly. A pair of input side piezoelectric ceramics 14a and 1 are provided on the input side longitudinal vibrating sound piece 2.
4b are superimposed and fixed using soldering or the like, and a pair of output side piezoelectric ceramics 16a and 1 are also attached to the output side longitudinal vibrating sound piece 4.
6b is polymerized and fixed. The support members 10 and 1
2 is fixed to the upper center of the upright pieces 24a and 24b of the U-shaped holding member 24 by laser welding or the like. The input side piezoelectric ceramics 14a and 14b of the composite longitudinal vibration mechanical filter configured in this manner
A supply line 18 and a grounding line 18e are connected between the output side piezoelectric ceramics 16a and 16b and the upright piece 24b for supplying a human power signal, while a lead line 20 for deriving an output signal is connected between the output side piezoelectric ceramics 16a and 16b and the upright piece 24b. and a grounding wire 20e are connected.

According to the above configuration, the input side longitudinal vibration sound piece 2 and the output side vertical vibration sound piece 4, which are connected in series by the coupling members 6 and 8, are arranged substantially in the air, and there is no obstacle to their longitudinal vibration operation. It is understandable that it is formed so that there is no such thing. The composite longitudinal vibration mechanical filter is housed in a frame (not shown) and then attached to an intermediate frequency amplification section of communication equipment, etc., to achieve its desired purpose.

In the composite longitudinal vibration mechanical filter configured as described above, a high frequency signal Sl from the signal source ○sc via the resistor R is attached between the supply line 18 and the ground line 188 on the input side piezoelectric ceramics 14a and 14b. The input side piezoelectric ceramics 14a and 14b are connected to an electrode (not shown) and connected to the input side longitudinal vibrating sound piece 2 which is electrically grounded.
An electric field corresponding to the high-frequency signal is generated through the This electric field causes the input side piezoelectric ceramics 14a and 14b to move in the thickness direction and in the directions indicated by arrows V and V in the figure. Electrostriction occurs in the direction shown in FIG. 2, and resonance occurs at a frequency F+ where the length of the input side longitudinally vibrating sound bar 2 is a half wavelength of the longitudinal wave. If the average propagation velocity of longitudinal waves in the input longitudinally vibrating acoustic bar 2 is V, the frequency F1 is given by the following equation.

F+ = 2 L+ /V ... (1) The longitudinal vibration at this frequency F+ is mechanically coupled to the output side longitudinal vibration sound bar 4 in the coupler members 6 and 8 and propagated, and the output side longitudinal vibration sound bar 4 resonates with longitudinal vibration at frequency F2 due to the length F2.This frequency F2 is calculated as follows, if the average propagation velocity of the longitudinal wave of the output longitudinal vibrating sound bar 4 is V, as in equation (1), then F2 = 2L2 /v ...(2) In the electric field generated in the output side piezoelectric ceramics 16a and 16b due to the longitudinal vibration of the output side vertically vibrating sound bar 4, the voltage generated in the unillustrated electrodes of the output side piezoelectric ceramics 16a and 16b is It is derived as a high frequency signal S2 formed with predetermined frequency characteristics between the derivation line 20 and the ground line 2Oe.

By the way, in this type of composite longitudinal vibration mechanical filter, separate input side and output side piezoelectric ceramics 14a, 14b, and 16a are used for the input side longitudinal vibration sound piece 2 and the output side vertical vibration sound piece 4, respectively, which are made of metal or the like. 16b is polymerized and fixed by soldering or the like. Furthermore, the state of polymerization and fixation becomes a factor that determines the reduction in voltage magnification (hereinafter referred to as Q value) or the insertion loss in the circuit network to which it is installed. Therefore, the input and output piezoelectric ceramics 14
a, 14b and 16a, 16b must be accurately fixed at predetermined positions on the input side and output side longitudinal vibrating sound bars 2 and 4.

In addition, the operating characteristics in the state where the input side and output side piezoelectric ceramics 14a, 14b and 16a, 16b are superimposed and fixed to the input side and output side longitudinal vibrating acoustic bars 2 and 4, respectively, are relatively complicated. Calculation and analysis are considered to be relatively difficult.

Further, in mass production work of polymer fixation, for example, work such as soldering, it is difficult to obtain uniform work, and it is relatively difficult to make the properties uniform.

[Object of the Invention] The present invention has been made in order to overcome the above-mentioned disadvantages. A holding means is provided to which a support member protruding from the vibrating body is attached, and the input side and output side vibrating bodies include an input side electrode formed of a conductive thin film to which a human power signal is supplied, and an output for deriving an output signal. The electrode is configured to be polymerized and fixed,
This allows the input and output side electrodes to be placed relatively accurately at predetermined positions on the piezoelectric member, and increases the degree of freedom in calculating and analyzing characteristics using only the constants of the piezoelectric member. The object of the present invention is to provide a composite longitudinal vibration mechanical filter whose characteristics can be made uniform in mass production by employing various members.

[Means for Achieving the Object] In order to achieve the above object, the present invention provides a composite longitudinal vibration mechanical filter that forms and derives a supplied high frequency signal into a predetermined frequency band. A plurality of vibrating bodies made of piezoelectric members including an output side, input and output side electrodes made of conductive thin films polymerized and fixed to the vibrating bodies on the input side and output side, and connected between the plurality of vibrating bodies. A coupling member, a supporting member formed on the input-side and output-side vibrating bodies, and a holding means to which the supporting member is fixed to hold the plurality of vibrating bodies and the coupling member in a hollow state. Features.

[Embodiment] Next, a preferred embodiment of the composite longitudinal vibration mechanical filter according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 2, reference numeral 30 indicates a composite longitudinal vibration mechanical filter, and the composite longitudinal vibration mechanical filter 30 includes an input longitudinal vibration acoustic bar 32 and an output longitudinal vibration acoustic bar 32 having the same shape as the input longitudinal vibration acoustic bar 32. It has a vibrating sound piece 34, and coupling members 36 and 38 that connect the input side and output side vertical vibration sound pieces 32 and 34. Further, support members 40 and 42 protrude from the center of the input side vertical vibration sound piece 32 and the output side vertical vibration sound piece 34, and a rectangular outer frame to which the ends of the support members 40 and 42 are connected to the inner end surface. Member 50
have.

All such materials are manufactured integrally from flat plates such as MT cut crystal members, x5° cut crystal members, 140° rotated Y plate LiNbo3 substrates, etc. using IJ lithography technology or press processing. Furthermore, as shown in the cross-sectional view between line ■-■ in FIG. 2 (FIG. 4), the input side longitudinal vibrating sound piece 32 is formed of a conductive solvent using a technique such as screen printing. In addition, input side electrodes 44a and 44b, such as thin films or metallization formed using vacuum evaporation, sputtering, etc., are fixed by polymerization. Similarly, output side electrodes 46a and 46b made of thin conductive films are superimposed and fixed on the output side longitudinally vibrating sound piece 34. Further, conductive wires 54 and 56 are formed on the front and back outer peripheral surfaces of the support members 40 and 42 and the outer frame member 50, respectively, to be connected to the input side electrodes 44a and 44b, and similarly, a conductive wire 58 is connected to the output side electrodes 46a and 46b. and 60 are formed. Additionally, conductors 54 and 56 are connected to connections 66 and 68, respectively, and to connections 72 to conductors 58 and 60, respectively.
and 74 are connected to each other.

Thereafter, supply lines 84a and 84b are connected to the connection parts 66 and 68 and the outer frame member 50, respectively, and the connection part 7
2 and 74 are connected to an output line 86a and a ground line 86e, respectively.
is connected.

In the composite longitudinal vibration mechanical filter 30 configured as described above, first, a signal source 0. . A high frequency signal S4, for example, a 455 KHz intermediate frequency signal generated from a frequency converter such as a superheterodyne receiver, is supplied via connections 66 and 68 through the resistor R. As a result, the input side electrode 44a is connected to the input side longitudinally vibrating sound piece 32.
and 44b, an electric field corresponding to the high frequency signal S is generated. This electric field causes the human arm side longitudinal vibrating sound piece 32 to move in the thickness direction and in the direction of the arrows m1 and m in the figure.

Electrostriction occurs in the direction shown in , and the input-side longitudinal vibrating sound bar 32 resonates at a frequency F3 where the length L3 is a half wavelength of the longitudinal wave. When the average propagation velocity of longitudinal waves in the input longitudinally vibrating acoustic bar 32 is V, the frequency F is given by the following equation.

F3 = 2L3 /V (3) This longitudinal vibration is mechanically coupled and propagated to the output side vertical vibration sound piece 34 in the coupling members 36 and 38, and the output side longitudinal vibration sound piece 34 is Resonance occurs due to longitudinal vibration of frequency F4.

The frequency F4 is the output side longitudinal vibrating sound bar 3 as in equation (3).
If the average propagation velocity of the longitudinal wave of 4 is V, then Fa”2L
4/V...(4) Due to the electrostriction caused by the longitudinal vibration of the output longitudinally vibrating sound bar 34, the electric field generated in the output electrodes 46a and 46b causes a voltage to be generated in the output electrodes 46a and 46b, and a voltage is generated due to the transmission of the longitudinal vibration. An intermediate frequency signal of, for example, 455 KILz formed to have a predetermined steep frequency characteristic, that is, a narrow band frequency characteristic, is derived as an output signal S5 between the output line 86a and the ground line 86e.

In the embodiment described above, two longitudinally vibrating sound bars are used, but the present invention is not limited to this, and for example,
As shown in FIG. 4, it is also possible to configure a plurality of vertically vibrating sound bars, three or more, in order to obtain steeper frequency characteristics. In other words, this complex longitudinal vibration mechanical
The filter 100 includes an input side vertically vibrating sound bar 102, an output side vertically vibrating sound bar 106, and a longitudinally vibrating sound bar 112.
．． 114 and 116 are coupling members 120 to 13, respectively.
4 are formed on the same surface. Furthermore, it includes an outer frame member 136 that surrounds the whole, and the outer frame member 136
The inner end surface of the support member 137 and the input side longitudinal vibrating sound piece 102
connected with. Similarly, the output side longitudinally vibrating sound piece 106 is connected by a support member 138. Like the composite longitudinal vibration mechanical filter 30, all such members are integrally manufactured from a flat plate such as an M'T cut crystal member using IJ lithography technology or press working.

Furthermore, the input side longitudinal vibrating sound piece 102 has a pair of, for example,
Thin film or vacuum deposition of conductors using screen printing,
Input side electrodes 104a and 104b formed of metallization or the like formed by the spunter method are polymerized and fixed.

Similarly, the output side electrode 10 is attached to the output side longitudinal vibrating sound piece 106.
8a and 108b are polymerized and fixed. Also, conductive wires 144 and 146 are formed on the front and back outer peripheral surfaces of the support members 137 and 138 and the outer frame member 136, respectively, to be connected to the input side electrodes 104a and 104b, and conductive wires 154 and 156 are formed on the output side electrodes 108a and 108b. It is formed. Connection portions 162 and 164 are connected to the conducting wires 144 and 146, respectively, and similarly, the conducting wire 154 is connected to the connecting portions 162 and 164, respectively.
Connection portions 172 and 174 are formed at and 156, respectively.

Thereafter, supply lines 182 and 184 are connected to the connection parts 162 and 164 and the outer frame member 136, respectively, and output lines 186 and 188 are connected to the connection parts 172 and 174 and the outer frame member 136, respectively.

In this way, when three or more longitudinally vibrating sound bars are constructed in order to form steeper frequency characteristics, there is an advantage in that the manufacturing process is particularly simplified.

The composite longitudinal vibration mechanical filters 30 and 100 shown in FIGS. 2 and 5 are housed in a frame, for example, as shown in FIG. 5, and used as a shock-resistant longitudinal vibration mechanical filter 200 or the like. In this impact-resistant longitudinal vibration mechanical filter 200, an insulating substrate 202 is provided with signal terminals 204a, 204b and signal deriving terminals 206a, 206b, and a frame member 208 made of plastic or the like that serves as an insulating spacer is provided on top of the terminals 204a, 204b and signal deriving terminals 206a, 206b. It will be placed.

Conductor layers 208a, 208b, 208f, and 208J are formed on the frame member 208. Furthermore, the composite longitudinal vibration mechanical filter 100 is fitted onto the upper part of the frame member 208. Further, a frame member 212 is placed on this composite longitudinal vibration mechanical filter 100. As a result, the composite longitudinal vibration mechanical filter 1
It will be understood that the longitudinal vibration sound pieces formed in the outer frame member 136 of No. 00 are arranged in a hollow state and have no effect on the operation of the longitudinal vibration. In addition, signal input terminals 204a, 2
04b is the conductor layer 208a, 20 provided on the frame material 208.
8b and further a composite longitudinal vibration mechanical filter 100
The connection portions 162 and 174 are connected using a separate conductor member (not shown) or the like.

On the other hand, the signal deriving terminals 206a and 206b are connected to the frame member 20.
The conductors 208f and 208j provided in the composite longitudinal vibration mechanical filter 100 are connected to each other using a separate conducting wire member or the like.

Furthermore, a lid plate 216 is attached to the upper part of the frame material 212.
It is placed so as to close the opening of No. 2, and each of the above-mentioned members is joined with screws or an adhesive to form a hermetically sealed state. With this configuration, the signal terminal 2 can be connected to the wiring on the surface of the printed circuit board (not shown).
04a, 204b and signal derivation terminals 206a, 20
A so-called surface-mount shock-resistant composite longitudinal vibration mechanical filter 200, etc., in which the filter 6b is fixed using soldering, is formed with a relatively simple member structure. This type of structure is sufficiently compatible with multilayer substrates or three-dimensional structures of substrates that are frequently used these days, and has the advantage of improving convenience and freedom of use.

In this way, a piezoelectric member is employed, and from the piezoelectric member, a vibrating body including an input side and an output side, a coupling member,
A support member and the like are integrally produced, and then a conductive thin film such as a solvent, input and output side electrodes such as metallization, etc. are formed on the input side and output side vibrators. Therefore, the characteristics can be calculated and analyzed using only the constants of the piezoelectric member, etc., and the degree of freedom during design is improved. Furthermore, when a single crystal member is adopted as a piezoelectric member, the manufacturing process is simplified due to its uniform characteristics, the manufacturing accuracy is improved, and mass production becomes possible. In order to obtain frequency characteristics, the manufacturing process is simplified, for example, when a large number of longitudinally vibrating acoustic bars are required.

[Effects of the Invention] As described above, according to the present invention, the vibrating bodies of the piezoelectric member including the input side and the output side are connected by the coupling member, and
The input side electrode and the output side vibrator are provided with a holding means to which support members protruding from the input side and output side vibrators are attached, and the input side electrode and the input side electrode formed of a conductive thin film are supplied with a human power signal to the input side and output side vibrator. By arranging the output electrodes for deriving the output signal to be superimposed and fixed, it is possible to relatively accurately arrange the input side and output side electrodes at predetermined positions on the piezoelectric member.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
For example, instead of forming the vertical vibration acoustic bar with a base plate having the same thickness as the coupling member, supporting member, outer frame member, etc., the longitudinal vibration acoustic bar may be formed to increase its thickness, or may be formed using other methods. Of course, various improvements and design changes are possible without departing from the gist of the present invention, such as making each member thinner.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of a composite longitudinal vibration mechanical filter according to the prior art, FIG. 2 is a perspective view showing the configuration of a composite longitudinal vibration mechanical filter according to the present invention, and FIG. 4 is a cross-sectional view along the line ■-■ of the composite longitudinal vibration mechanical filter; FIG. 4 is a perspective view showing an example of an embodiment in which the composite longitudinal vibration mechanical filter according to the present invention is configured with five longitudinal vibration bars; FIG. 5 is a perspective view showing an example of the composite longitudinal vibration mechanical filter shown in FIG. 3 configured as a surface mount type. 30...Compound longitudinal vibration mechanical filter 32...
Input side vertical vibration sound piece (piezoelectric member) 34...Output side vertical vibration sound piece (piezoelectric member) 36.38...Coupling member 40
．． 42...Support members 44a, 44b...Input side electrodes 46a, 46b...Output side electrode 50...Outer frame member 54.56...Input side electrode conductor 58.60...Output side Electrode conductor 66.68... Connection part (for input side electrode) 76.78.
...Connection part (for output side electrode) 100...Compound longitudinal vibration mechanical filter 200...Shock-resistant compound mechanical filter FIG, 5

Claims (1)

[Claims] (1) A composite longitudinal vibration mechanical filter that forms and derives a supplied high-frequency signal into a predetermined frequency band, which includes a plurality of vibrating bodies made of piezoelectric members including an input side and an output side, and Input side and output side electrodes made of conductive thin films polymerized and fixed to the output side vibrating body, a coupling member connected between the plurality of vibrating bodies, and a support formed on the input side and output side vibrating bodies. 1. A composite longitudinal vibration mechanical filter comprising a holding means to which a member and the supporting member are fixed and holding the plurality of vibrating bodies and the coupling member in a hollow state.